title: PML overexpression inhibits proliferation and promotes the osteogenic differentiation of human mesenchymal stem cells.
abstract: The promyelocytic leukemia (PML) gene, as an important tumor-suppressor, has been proven to regulate stem cell function in multiple tissues; however its role in human mesenchymal stem cells (hMSCs) remains unclear. In the present study, the effect of PML on regulating the proliferation and osteogenic differentiation of hMSCs was explored. New downstream genes that may be responsible for the regulation of PML were found, and possible mechanisms were analyzed. The lentiviral vector which encodes full-length human PML cDNA or shRNA against PML was transfected into hMSCs. RT-PCR and western blotting were used to detect mRNA and protein expression. Flow cytometry was used to analyze apoptosis and the cell cycle distribution. Osteogenic differentiation of hMSCs was induced by osteo-inductive medium for 7 to 14 days. cDNA microarray was used to scan the gene expression profile and to identify significant changes in gene expression. In the present study, we found that PML was stably expressed in hMSCs, and the expression was increased time-dependently along with cell osteogenic differentiation. Overexpression of PML inhibited hMSC proliferation by inducing apoptosis and arresting the cell cycle. However, PML enhanced the osteoblast differentiation potential of hMSCs. PML-overexpressing hMSCs had a significant increase in mineralized matrix production and ALP activity on day 7 under osteogenic or non-osteogenic differentiation conditions. Upregulation of integrin-binding sialoprotein (IBSP, bone sialoprotein) induced by PML overexpression was found. Our data indicate that PML regulates hMSCs as an inhibitor of cell proliferation but a promoter of osteogenic differentiation.
authors.affiliation: The First Affiliated Hospital, Medical School of Zhejiang University, Hangzhou 310003, P.R. China.
authors.forename: Jie
authors.initials: J
authors.lastname: Sun
authors.forename: Shan
authors.initials: S
authors.lastname: Fu
authors.forename: Weijun
authors.initials: W
authors.lastname: Zhong
authors.forename: He
authors.initials: H
authors.lastname: Huang
mesh_terms: D017209:Apoptosis / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics; D002460:Cell Line; D049109:Cell Proliferation; D018076:DNA, Complementary / Q000235:genetics; D005786:Gene Expression Regulation; D006801:Humans; D058574:Integrin-Binding Sialoprotein / Q000096:biosynthesis; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism*; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D010012:Osteogenesis / Q000235:genetics*; D000071156:Promyelocytic Leukemia Protein; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics*; D025521:Tumor Suppressor Proteins / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D018076:DNA, Complementary; C546871:IBSP protein, human; D058574:Integrin-Binding Sialoprotein; D009687:Nuclear Proteins; D000071156:Promyelocytic Leukemia Protein; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; C070576:PML protein, human